Two-part interface materials, systems including the interface material, and methods thereof

ABSTRACT

The teachings herein relate to new compositions for thermal interface materials that provide improved thermal conductivity without requiring filler materials that are expensive or abrasive. The improved thermal conductivity is achieved using a combination of increased filler loading, selection of a filler having abroad particle size distribution, and selection of filler that is non-abrasive. The thermal interface material preferably has a specific gravity of about 4.0 or less, about 3.0 or less, about 2.5 or less, or about 2.4 or less. The thermal interface material may be a two-part composition. In order to achieve maximum thermal conductivity, each part preferably includes a liquid matrix material and dispersed filler. Upon mixing, the first and second parts may react to increase this viscosity (e.g., by polymerizing and/or cross-linking). The first part preferably includes a carbamate-containing compound that reacts with a carbamate-reactive compound, which is preferably in the second component. The first part preferably is substantially or entirely free of isocyanate containing compounds, as these compounds may reduce the shelf life stability of the composition. The carbamate-reactive compound preferably is a polyamine, including two or more spaced apart amine groups. The first part, the second part, or both, preferably includes a catalyst for accelerating the reaction between the carbamate-containing compound and the carbamate-reactive compound.

FIELD

The teachings herein are directed to thermal interface materials havinggenerally high thermal conductivity, components and articles includingthe thermal interface material, and related methods. The thermalinterface material is preferably formed of a two-part composition, whereeach part includes a matrix phase that is a liquid at room temperatureand one or more thermally conductive fillers dispersed in the matrixphase. The matrix phase of the first part preferably includes acarbamate containing compound and the matrix phase of the second partpreferably includes a carbamate-reactive compound.

BACKGROUND

The automotive industry has seen a trend to reduce the weight of thevehicles in the past decade. This lightweight trend has been mainlydriven by regulations to reduce the CO₂ emission of the vehicle fleet.In recent years lightweight construction strategies have been furtherfueled by the increasing number of electrically driven vehicles. Thecombination of a growing automotive market and a growing market share ofelectrically powered vehicles leads to a strong growth in the number ofelectrically driven vehicles. To provide long driving ranges batterieswith a high energy density are needed. Several battery strategies arecurrently followed with differing detailed concepts, but what alllong-range durable battery concepts have in common is that a thermalmanagement is needed. In particular, to thermally connect battery cellsor modules to a cooling unit, thermal interface materials, based ontwo-part reactive compositions, are needed.

Various composition include conductive fillers and two-part reactivecompositions are described in PCT Patent Application numbers WO2001/041213 A1: WO 2014/047932 A1, WO 2015/148318 A1; WO 2016/145651 A1;WO 2017/091974 A1; WO 2018/34721; and WO 2006/016936 A1; European PatentApplication EP 1438829 A1; Japan Patent Application JP 2010/0138357 A;and US Patent Application US 2009/0250655 A1; each incorporated byreference herein in its entirety. In these prior attempts, thecompositions suffered on one or more of the needs for an affordablethermal interface material, such as the thermal conductivity of thecomposition is insufficient, the composition is difficult to produce,the composition does not properly fill gaps so that the contact isinsufficient; the components of the composition do not react at roomtemperature, one or both of the components has poor shelf lifestability, the composition requires expensive material; or thecomposition requires abrasive filler that can damage processingequipment.

There continues to exist a need for a thermal interface material (andparticularly a two-part composition) having both high thermalconductivity and low viscosity. There is also a continuing need forthermal interface materials having filler materials that arenon-abrasive. There is also a continuing need for thermal interfacematerials that are more economical with respect to raw material costsand/or manufacturing/processing costs. There is also a need for atwo-part composition having high filler content that is able to flow atroom temperature to fill a gap. There is also a need for a materialmeeting one or more of the above needs that also has one or more of thefollowing features: shelf stable (e.g., maintain ability to flow at roomtemperature after aging); ability to react at room temperature topolymerize, cross-link or both; good thermal conductivity; substantiallyor entirely avoids use of abrasive filler; or is light weight (e.g.,having a specific gravity of about 3 or less, about 2.8 or less, about2.6 or less, about 2.5 or less, or about 2.4 or less).

SUMMARY

One or more of the above needs may be achieved using a thermal interfacematerial according to the teachings herein.

A first aspect of the teachings herein is direct to a two-partcomposition for a thermal interface material comprising: a first partcomprising at least a prepolymer including two or more carbamate groups;and a second part comprising at least one or more polyamine compoundscapable of a reaction with the prepolymer. The composition preferablyincludes (in the first part, the second part, or both) one or morecatalysts for catalyzing the reaction between the prepolymer and thepolyamine compounds; and 50 weight percent or more of one or moreconductive fillers, based on the total weight of the two-partcomposition.

A second aspect of the invention is a method comprising a step of:arranging a layer of a thermal interface material according to theinvention between a first component and a second component, and applyinga pressure so that the thermal interface material contacts both thefirst component and the second component and fills a gap between the twocomponents.

DETAILED DESCRIPTION

The first aspect may be further characterized by one or any combinationof the following features: the prepolymer is formed by blocking one ormore of the isocyanate groups (preferably substantially each, orentirely each of the isocyanate groups) of an aromatic polyisocyanateprepolymer with a phenol group of a blocking compound; the blockingcompound includes a terminal phenol group (preferably a single terminalphenol group) attached to a linear hydrocarbon (preferably the linearhydrocarbon includes 6 or more, 8 or more, 10 or more, or 12 or morecarbon atoms) (preferably the linear carbon includes 60 or less, 30 orless, or 20 or less carbon atoms); the one or more polyamines, theprepolymer, or both have an average functionality of greater than 2; theone or more thermally conductive fillers are preferably selected fromaluminum hydroxide, aluminium oxide, aluminium powder, zinc oxide, boronnitride, and mixtures of these; the first part includes 75 weightpercent or more thermally conductive fillers preferably selected fromaluminum hydroxide, aluminium oxide, aluminium powder, zinc oxide, boronnitride, and mixtures of these; the second part includes 75 weightpercent or more of a thermally conductive filler preferably selectedfrom aluminum hydroxide, aluminium oxide, aluminium powder, zinc oxide,boron nitride, and mixtures of these; preferably a surface of thethermally conductive filler, for example aluminum hydroxide, ispartially or entirely coated with a surface modifier for reducing thehydrophilicity of the surface; the composition includes a thermallyconductive filler preferably selected from aluminum hydroxide, aluminiumoxide, aluminium powder, zinc oxide, boron nitride, and mixtures ofthese having a broad particle size distribution as characterized by aD₉₀/D₅₀ ratio of about 3 or more; the composition preferably includesone or more plasticizers; the composition preferably includes a fattyacid or an ester of a fatty acid; the composition comprises an epoxyresin in the first part; a weight ratio of the prepolymer to the epoxyresin is about 0.5 or more, more preferably about 0.8 or more, even morepreferably about 1.0 or more; a weight ratio of the prepolymer to theepoxy resin is about 10 or less, about 5 or less, or about 4 or less;the composition is substantially free of isocyanate containingcompounds; the amount of NCO in the first-part is about 0.10 weightpercent or less, about 0.05 weight percent or less, or about 0.01 weightpercent or less, based on the total weight of the first part; a molarratio of the carbamate groups in the first part to the amine groups inthe second part is about 0.1 or more, about 0.2 or more, about 0.3 ormore, about 0.4 or more, about 0.5 or more, or about 0.6 or more; amolar ratio of the carbamate groups in the first part to the aminegroups in the second part is about and/or about 10 or less, about 5.0 orless, about 3.5 or less, about 2.5 or less, about 2.0 or less, or about1.7 or less; the first part includes calcium carbonate; the amount ofcalcium carbonate in the first part and/or in the composition is about0.1 weight percent or more, preferably about 0.5 weight percent or more,or about 1.0 weight percent or more; the first part includes some or allof the catalyst; the composition is characterized by a thermalconductivity of about 2.0 W/mK or more, preferably about 2.5 or more,more preferably about 2.8 or more, even more preferably about 2.9 ormore, and most preferably about 3.0 or more, according to ASTM 5470-12on a therma interface material tester from ZFW Stuttgart, with testsperformed in Spaltplus mode at a thickness of between 1.8-1.2 mm. Thedescribed thermal interface material is considered as Type I (viscousliquids) as described in ASTM 5470-12. The upper contact is heated to ca40° C. and the lower contact to ca 10° C., resulting in a sampletemperature of ca 25° C. The A and B component are mixed with a staticmixer when applied from a manual cartridge system; the two-partcomposition cures at room temperature (preferably as characterized by anincrease in a press-in force of about 60% or more, or about 100% ormore, after aging for 24 hours after mixing); the first part is shelfstable (e.g., as characterized by a press-in force of the first part ofless than 700 N after aging for 3 days at 55° C.); or the two-partcomposition is characterized by a specific gravity of about 2.5 or less.

Another aspect according to the teachings herein is directed to anarticle comprising: a first component that generates heat, a secondcomponent for removing heat, and a layer of a thermal interface materialinterposed between the first and second components, wherein the thermalinterface material provides a path for transferring a heat from thefirst component to the second component. The thermal interface materialis preferably formed by a two-part composition according to theteachings herein.

Another aspect according to the teachings herein is directed at a methodcomprising a step of: arranging a layer of a thermal interface materialbetween a first component and a second component, and applying apressure so that the thermal interface material contacts both the firstcomponent and the second component and fills a gap between the twocomponents. The thermal interface material is preferably formed of atwo-part composition according to the teachings herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing illustrating features of a composition having afiller with a generally narrow particle size distribution (A), acomposition having a filler with a generally broad particle sizedistribution (B), and a composition having a filler with a generallybroad particle size distribution that has been surface modified (C).

FIG. 2 is a drawing illustrating features of a reaction between asurface modifier and a conductive filer. For example, a surface modifiermay change the hydrophobicity of the surface.

FIG. 3 is a drawing showing illustrative composition having differentamounts of filler where the filler (A) has a narrow particle sizedistribution; (B) has a broad particle size distribution, and (C) has abroad particle size distribution and a surface modifier to reduce orminimize the bonding between the matrix phase material and the filler.

FIG. 4 is an optical micrograph of an illustrative conductive fillerhaving a broad particle size distribution.

FIG. 5 is a drawing showing illustrative features of a device includinga thermal interface material.

FIG. 6 is an illustrative drawing of a battery including a thermalinterface material.

FIG. 7 is a drawing illustrating various chemical reactions which may beemployed or avoided according to the teachings herein.

DETAILED DESCRIPTION

Unless otherwise specified, the term “consisting essentially of”includes an amount of about 90 weight percent or more, about 95 weightpercent or more, about 98 weight percent or more, or about 99 weightpercent or more.

Unless otherwise specified the term “conductive” and “conductivity”refers to “thermally conductive” and “thermal conductivity”.

The thermal interface material includes two or more phases andpreferably includes two phases. A first phase of the thermal interfacematerial is a matrix phase. The matrix phase preferably is a continuousphase. However, the matrix phase may be a co-continuous phase and/orinclude one or more sub-phases. Preferably the matrix phase includes,consists essentially of, or consists entirely of one or more polymers,oligomers, or polymerizable compounds. The matrix phase preferablyincludes, consists essentially of, or consists entirely of one or morematerials that are liquid at room temperature or require minimal heatingto become a liquid. The second phase is a discrete phase that isdispersed in the matrix phase. It will be appreciated that the discretephase may be coated with one or more additional phases that provides aninterface between the discrete phase and the matrix phase. Typically,the matrix phase includes materials having generally low thermalconductivity (e.g., about 1 W/mK or less, or about 0.2 W/mK or less) sothat thermal conductivity of the composition relies primarily on thediscrete phase. The discrete phase includes one or more filler materialsthat are solid at room temperature. Because the filler phase is requiredto provide much of the thermal transport, it is necessary to includehigh concentrations of the filler to overcome the fact that the fillerparticles are generally dispersed in the matrix phase.

The thermal interface material may be formed from a single composition,or may be formed by combining two or more parts, each having a differentcomposition. For example, the thermal interface material may be formedby mixing a first part (A-component) and a second part (i.e.,B-component) of a two-part composition. Typically, upon mixing, thematrix phase of the composition is formed by combining a matrix phase ofeach part. The combined matrix phase preferably is reactive so that themolecular weight of one or more compounds in the matrix phase isincreased. As one example, a compound in the first part may react with acompound in the second part. As another example, a reaction of acompound in the first part may be accelerated by a catalyst in thesecond part. The reaction may be any reaction that increases theviscosity of the matrix phase. Preferably, the reaction includes apolymerization reaction, a cross-linking reaction, or both. In someapplications, the thermal interface material is contacted with atemperature sensitive component and it is desirable to avoid heating thecomponent to a temperature at which it can degrade or lose performance.Preferably, the reaction is capable of proceeding at a reactiontemperature of about 50° C. or less, about 40° C. or less, about 30° C.or less, or about 23° C. or less. Preferable, the reaction is capable ofproceeding at a reaction temperature of about −10° C. or more, about 0°C. or more, or about 10° C. or more. For example, the reaction may occurat about room temperature (e.g., about 23° C.). If the reaction isexothermic, the increase in temperature due to this released energytypically is about 30° C. or less, about 20° C. or less, or about 10° C.or less. In some applications, it is desired for the reaction to occurquickly (e.g., in a time of about 1 hour or less). However, it ispreferred that the reaction occurs over a longer period of time so thatsharp temperature increases are avoided. Preferably, the reaction timemay be about 30 minutes or more, more preferably about 1 hour or more,even more preferably about 4 hours or more, even more preferably about 8hours or more, and most preferably about 24 hours or more. The reactiontime typically is about 30 days or less, about 15 days or less, or about7 days or less.

When the thermal interface material is provided as a two-partcomposition, the two parts may be combined at any convenient volumeratio. The volume ratio of the first part to the second part may beabout 100:1 or less, about 10:1 or less, about 3:1 or less, about 2:1 orless, or about 1:1 or less. The volume ratio of the first part to thesecond part may be about 1:100 or more, about 1:10 or more, about 1:3 ormore, about 1:2 or more, or about 1:1 or more. The first part and secondpart may be packaged separately. The first part and the second part maybe packaged in a single container, typically with the two partsseparated to avoid contact and/or mixing prior to use.

The thermal interface material typically has a specific gravity of about1.50 or more, or about 1.8 or more, due to the filler in thecomposition. In some applications, such as in transport, it may bedesirable for the thermal interface material to be light weight.Preferably, the thermal interface material has a specific gravity ofabout 4.0 or less, more preferably about 3.0 or less, even morepreferably about 2.5 or less, even more preferably about 2.4 or less,and most preferably about 2.3 or less.

Fillers

The compositions according to the teachings herein include one or morefillers for increasing the thermal conductivity of the composition.Although the filler may include an ultra high conductivity filler (e.g.,a filler having a thermal conductivity of about 100 W/mK), such fillersare typically abrasive and/or expensive. Preferably, the one or morefillers includes, consists essentially of, or consists entirely of oneor more conductive fillers having thermal conductivity of about 80 W/mKor less, about 50 W/mK or less, about 30 W/mK or less, about 20 W/mK orless, or about 15 W/mK or less. The conductive filler preferably has athermal conductivity of about 3 W/mK or more, about 4 W/mK or more,about 5 W/mK or more, or about 6 W/mK or more. The conductive filler maybe characterized by a thermal conductivity of about 10+/−10%, about10+/−20%, or about 10+/−30%. Preferably, the amount of ultra highconductivity filler in the composition is about 15 weight percent orless, more preferably about 4 weight percent or less, even morepreferably about 1 weight percent or less, and most preferably about 0.3weight percent or less, based on the total weigh of the one or morefillers. The amount of ultra high conductivity filler in the compositionmay be about 0.0 percent or more, based on the total weight of the oneor more fillers. The amount of the conductive filler (i.e., excludingultra high conductivity filler) may be about 80 weight percent or more,about 85 weight percent or more, about 90 weight percent or more, about93 weight percent or more, about 96 weight percent or more, about 98weight percent or more, about 99 weight percent or more, or about 99.7weight percent or more, based on the total weight of the one or morefillers. The amount of the conductive filler may be about 100 weightpercent or less, based on the total weight of the one or more fillers.

The ultra high conductivity filler, if present, may be any filler have athermal conductivity of about 100 W/mK. Examples of ultra highconductivity fillers include boron nitrides and aluminum powder.

The conductive filler may be any filler having a thermal conductivitysuch as described herein. For example, the conductive filler may have athermal conductivity of about 3 W/mK to about 80 W/mK. The conductivefiller preferably is non-abrasive (e.g., is less abrasive thanboronnitride, less abrasive than aluminum powder, or both). An exampleof a non-abrasive conductive filler is aluminum hydroxide (i.e., ATH)powder. Aluminum hydroxide powder has a thermal conductivity between 3and 80 W/mK (typically about 10 W/mK).

The conductive filler typically includes one or more metal or metalloidatoms and one or more atoms that is a nonmetal. Metalloid atoms includeboron, silicon, germanium, arsenic, antimony, and tellurium. Preferredmetal atoms include alkali metals, alkaline earth metals, transitionmetals, and post-transition metals. The amount of nonmetal atoms in theconductive filler should be sufficiently high so that the conductivefiller is not hard and abrasive. Examples of metal or metalloidcontaining fillers that are hard and abrasive include SiC, TiC, and BN.These hard and abrasive fillers include 50 atomic percent of the metalor metalloid. Preferably the concentration of the nonmetal atoms in theconductive filler is more than about 50 atomic percent nonmetal atoms,more preferably about 65 percent or more, even more preferably about 75percent or more, and most preferably about 80 percent or more, based onthe total number of atoms in the conductive filler. The concentration ofthe nonmetal atoms may be about 95 atomic percent or less, about 93atomic percent or less, about 90 atomic percent or less or about 88atomic percent or less. The conductive filler preferably has asufficient concentration of metal atoms so that the thermal conductivityis about 3 W/mK. The combined concentration of any metal and metalloidin the conductive filler preferably is about 5 atomic percent or more.The combined concentration of any metal and metalloid in the conductivefiller may be less than 50 atomic percent, about 35 atomic percent orless, about 25 atomic percent or less, or about 20 atomic percent orless.

Preferred compositions include a sufficient amount of the conductivefiller so that the thermal conductivity of the composition is about 1.5W/mK or more, preferably about 2.0 W/mK or more, more preferably about2.5 W/mK or more, and most preferably about 3.0 W/mK or more. Thethermal conductivity of the composition is typically about 10 W/mK orless, about 7 W/mK or less, or about 5 W/mK or less, measured accordingto ASTM 5470-12 on a therma interface material tester from ZFWStuttgart, with tests performed in Spaltplus mode at a thickness ofbetween 1.8-1.2 mm; the described thermal interface material isconsidered as Type I (viscous liquids) as described in ASTM 5470-12, theupper contact is heated to ca 40° C. and the lower contact to ca 10° C.,resulting in a sample temperature of ca 25° C.

The A and B component are mixed with a static mixer when applied from amanual cartridge system. If the amount of the conductive filler is toolow, the composition will not be able to conduct heat sufficiently formanaging the temperature of a device. In order to achieve such highthermal conductivity of the composition, the composition typically hashigh concentrations of the conductive filler. Preferably, the amount ofthe conductive filler in the composition is about 60 weight percent ormore, more preferably about 70 weight percent or more, even morepreferably about 75 weight percent or more, even more preferably about80 weight percent or more, even more preferably about 85 weight percentor more, and most preferably about 88 weight percent or more, based onthe total weight of the composition. The amount of the conductive fillerin the composition should be sufficiently low so that the conductivefiller can be dispersed in the matrix. Typically, the amount ofconductive filler is about 95 weight percent or less, more preferablyabout 92 weight percent or less, based on the total weight of thecomposition.

The conductive filler preferably has a sufficiently low Mohs hardness sothat it is generally non-abrasive. Preferably, the conductive filler hasa Mohs hardness of about 7.0 or less, preferably about 5.0 or less, andmore preferably about 4.0 or less. The conductive filler may have a Mohshardness of about 0.5 or more, about 1.5 or more, or about 2.0 or more.

The conductive filler typically includes M-X bonds, where M is a metaland X is a non-metal. Preferably the ratio of the M-X bonds to the M-Mbonds (metal-metal bonds) in the filler may be about 2.0 or more, about3.0 or more, or about 4.0 or more. It will be appreciated, that theconductive filler may be free of M-M bonds. An example of a conductivefiller that is generally free of M-M bonds is aluminum hydroxide.

The one or more fillers in the composition preferably has an averagespecific gravity of about 3.5 or less, more preferably about 3.0 orless, even more preferably about 2.8 or less, even more preferably about2.6 or less and most preferably about 2.5 or less. The average specificgravity of the one or more fillers may be about 1.8 or more, about 2.2or more, or about 2.4 or more. The average specific gravity of a fillersincluding a mass fraction m_(a) of filler A having specific gravityv_(a) and a mass fraction m_(b) of filler B having a specific gravityv_(b) (where m_(a)+m_(b)=1) is defined as:

1/[(m_(a)/v_(a))+(m_(b)/v_(b))].

In addition to the thermally conductive filler, other fillers mayinclude calcium carbonate and/or calcium oxide. If employed, the totalamount of the calcium carbonate and the calcium oxide preferably isabout 20 weight percent or less, more preferably about 10 weight percentor less, and most preferably about 5 weight percent, based on the totalweight of the one or more fillers. The total amount of the calciumcarbonate and the calcium oxide may be about 0 weight percent or more,about 0.4 weight percent or more, or about 0.8 weight percent or more,based on the total weight of the one or more fillers in the composition(e.g., in the two part composition).

Preferred fillers are selected from aluminum hydroxide, aluminium oxide,aluminium powder, zinc oxide, boron nitride, and mixtures of these.Particularly preferable the filler is selected from aluminium hydroxide,aluminium oxide and mixtures of these. Most particularly preferred isaluminium hydroxide.

Particle Size Distribution

In order to achieve a combination of high thermal conductivity of thecomposition and ability to mix and process the composition, theconductive filler preferably has a broad particle size distribution.

The broad particle size distribution may allow the particles to moreefficiently pack together. The particle size distribution may becharacterized by D₁₀, D₅₀, and D₉₀, corresponding to the 10thpercentile, 50th percentile (median), and 90th percentile of theparticle sizes. Particle size is measured according to ISO 13320, usinga 2.24×10⁻³ M solution of Tetrasodium pyrophosphate decahydrate (1 gNa₄P₂O₇X10H₂O in 1000 ml deionized water) as dispersion medium.

Filler having a broad particle size distribution may be characterized byone or more of the following: a generally high ratio of D₉₀/D₅₀, agenerally high ratio of D₉₀/D₁₀, or a generally high ratio of D₅₀/D₁₀,or any combination thereof. Preferably, the ratio of D₉₀/D₅₀ is about 3or more, about 4 or more, about 5 or more, about 6 or more or about 8 ormore. The ratio of D₉₀/D₅₀ may be about 100 or less or about 40 or less.Preferably the ratio of D₉₀/D₁₀ is about 20 or more, about 40 or more,about 60 or more, or about 80 or more. The ratio of D₉₀/D₁₀ may be about1000 or less or about 400 or less. The ratio of D₉₀/D₅₀ may be about 100or less or about 40 or less. Preferably the ratio of D₅₀/D₁₀ is about 8or more, about 10 or more, or about 12 or more. The ratio of D₅₀/D₁₀ maybe about 100 or less or about 40 or less. The large particles in theconductive filler (as characterized by the D₉₀ value) should besufficiently high so that sites are created for packing one or moresmaller particles. Preferably D₉₀ is about 10 μm or more, morepreferably about 20 μm or more, even more preferably about 40 μm ormore, and most preferably about 60 μm or more. If D₉₀ is too large, itmay be difficult to process the composition. Preferably, D₉₀ is about2000 μm or less, more preferably about 1000 μm or less and mostpreferably about 500 μm or less. The small particles (as characterizedby the D₁₀ value) in the conductive filler should be sufficiently smallso that they can fit in sites between large particles. Preferably, D₁₀is about 4 μm or less, about 2 μm or less, or about 1 μm or less.Typically, it is difficult and costly to make very small particles. Assuch, it is preferable that D₁₀ is about 0.1 μm or more, or about 0.25μm or more, although smaller particles may be employed. The conductivefiller may have a first portion having an average particle size of about10 μm or less, and a second portion having an average particle size ofabout 50 μm or more (preferably, the first and second portions are eachpresent in an amount of about 25 weight percent or more, about 30 weightpercent or more, or about 35 weight percent or more of the conductivefiller).

FIG. 1 illustrates the effect of having a broad particle sizedistribution 6 (B) on the ability to pack small particles 7 betweenlarger particles 8 as compared to a filler having a narrow particle sizedistribution 4 (A). With the increase in particle concentration using abroad particle size distribution, particles 2 are closer and there maybe bridging between two particles by the matrix phase material 3.Adhesion of the matrix phase to the particle surface and/or bridging mayreduce the ability to flow or process the composition. In order toimprove processability, the particles preferably have surface modifier.For example (C) has a broad particle size distribution 6 and a coating 5(e.g., of a surface modifier) to reduce or minimize the bonding betweenthe matrix phase material and the filler.

FIG. 2 is an optical micrograph of an example of a conductive filler,aluminum hydroxide (i.e., Al(OH)₃) having a broad particle sizedistribution.

Filler Surface Modifier

Although in many filled polymer systems, it is desirable to have goodcompatibility and/or bonding between the matrix phase and the fillerphase, Applicant has determined that for these highly filledcompositions, such compatibility and/or bonding may create bridgesbetween neighboring filler particles that prevent the flow of thecomposition. It is preferred that the matrix phase material does notbond with a surface of the filler. For example, the covalent bonding,ionic bonding, and hydrogen bonding may be reduced, minimized or evencompletely avoided. This can be achieved by selection of the matrixphase material and conductive filler material. Alternatively, the fillermaterial may be treated with one or more surface modifiers for reducing,minimizing or eliminating bonding with the matrix phase material.

The surface modifier may partially or completely cover the surface ofthe conductive filler particle. The surface modifier may have one ormore functional groups that reacts with the conductive filler particle.As such, the surface modifier may be covalently bonded to the conductivefiller. By way of example, the conductive filler may include M-OHgroups, where Mis a metal atom, and the surface modifier may include afunctional group that reacts with the M-OH group to form a direct orindirect bond between the surface modifier and M.

The surface of the conductive filler may be hydrophobized with thesurface modifier. For example, the surface modifier may include an alkylcomponent and one or more functional group at or near one end of thealkyl component. The alkyl component preferably includes about 6 or morecarbon atoms, more preferably about 8 or more carbon atoms, even morepreferably about 10 or more carbon atoms, and most preferably about 12or more carbon atoms. The one or more functional groups may be selectedto react with surface of the conductive filler. For example, the one ormore function groups may include one or more alkoxysilanes. Such afunctional group may be particularly useful for bonding the surfacemodify to a conductive filler including M-OH groups, such as in aluminumhydroxide. An example of a reaction between a conductive filler and asurface modifier is shown in FIG. 3.

It will be appreciated that the surface modifier may be added to thefiller before or after mixing the conductive filler with the matrixphase material. For example, the conductive filler may be coated and/orreacted with the surface modifier prior to mixing the conductive fillerand the matrix phase material. As another example, the surface modifiermay be mixed with the matrix phase material to form a premix which isthen combined with the conductive filler. As another example, theconductive filler and the matrix phase material may be mixed and thenthe surface modifier may be added to the mixture.

Matrix Phase

The matrix phase of the thermal interface material typically includes,consists essentially of, or consists entirely of one or more liquidmaterials. For example, the matrix phase of the first part, the secondpart, or both may include one or more materials that are liquid at roomtemperature. The amount of the liquid compounds in the first part, thesecond part, or both, preferably is about 50 weight percent or more,more preferably about 70 weight percent or more, even more preferablyabout 85 weight percent or more, even more preferably about 95 weightpercent or more, and most preferably about 98 weight percent or more,based on the total weight of the matrix phase of the part. The amount ofthe liquid compounds in the first part, the second part, or both, may beabout 100 weight percent or less, based on the total weight of thematrix phase of the part. As the matrix phase is preferably a minorphase (i.e., present in amount of about 50 volume percent or less of thecomposition) the amount of the liquid compounds in the first part, thesecond part, or both is preferably about 50 volume percent or less,based on the total weight of the part. The one or more liquids should bepresent in an amount sufficient so that each part can be mixed withoutcrumbling. Preferably, the weight percent of the one or more liquidcompounds in the first part, the second part, or both is about 3 weightpercent or more, about 5 weight percent or more, or about 7 weightpercent or more, based on the total weight of the part. The one or moreliquids should be present in an amount sufficiently low so that theseparation between filler particles is reduced and the thermalconductivity of the part or the entire composition is about 2.0 W/mK ormore, about 2.5 W/mK or more, about 2.8 W/mK or more, about 2.9 W/mK ormore, or about 3.0 W/mK or more, measured according to ASTM 5470-12 on atherma interface material tester from ZFW Stuttgart, with testsperformed in Spaltplus mode at a thickness of between 1.8-1.2 mm; thedescribed thermal interface material is considered as Type I (viscousliquids) as described in ASTM 5470-12, the upper contact is heated to ca40° C. and the lower contact to ca 10° C., resulting in a sampletemperature of ca 25° C. Preferably, the one or more liquid compounds inthe first part, the second part, or both is about 30 weight percent orless, more preferably about 25 weight percent or less, even morepreferably about 20 weight percent or less, even more preferably about15 weight percent or less, and most preferably about 13 weight percentor less, based on the total weight of the part.

The total amount of the matrix phase in the thermal interface material(e.g., after mixing the first and second parts, and optionally afterreacting the two parts), preferably is about 30 weight percent or less,more preferably about 25 weight percent or less, even more preferablyabout 20 weight percent or less, even more preferably about 15 weightpercent or less, and most preferably about 13 weight percent or less,based on the total weight of the composition. The total amount of thematrix phase in the thermal interface material (e.g., after mixing thefirst and second parts, and optionally after reacting the two parts),preferably is about 3 weight percent or more, more preferably about 5weight percent or more, even more preferably about 7 weight percent ormore, and most preferably about 8 weight percent or more, based on thetotal weight of the composition.

The first part (i.e., the carbamate-containing part) includes one ormore carbamate-containing compounds. The carbamate-containing compoundmay be any compound including a carbamate group, and preferablyincluding two or more spaced apart carbamate groups. Spaced apartcarbamate groups are typically separated by 6 or more, 10 or more, or 15or more atoms on the backbone of the compound. The carbamate-containingcompound may be a monomer, an oligomeric compound. An oligomericcompound may be a prepolymer. The carbamate-containing compound may beprepared by reacting an isocyanate-containing compound with aphenol-containing compound to form the carbamate group. Thecarbamate-containing com

It will be appreciated that a carbamate-containing compound includingtwo or more carbamate groups may be formed by i) reacting isocyanategroups in an isocyanate-containing compound with a phenol-containingcompound having a single phenol group, where the isocyanate-containingcompound includes two or more spaced apart isocyanate groups; or ii)reacting each phenol group in a phenol-containing compound with anisocyanate-containing compound having a single isocyanate group, wherethe phenol-containing compound includes two or more spaced apart phenolgroups. Typically, the spaced apart isocyanate groups or the spacedapart phenol groups are separated by 6 or more, 10 or more, or 15 ormore atoms on the backbone of the compound.

The first part and/or the entire two-part composition preferably issubstantially free of isocyanate-containing compounds so that the partand composition have good shelf life stability. Without being bound bytheory, it is believed that the high concentration of filler and/oramounts of water in the filler may result in polymerization and/orcross-linking of the isocyanate-containing compound, resulting in anincrease in the viscosity or even setting of the first part. Preferablythe amount isocyanate groups in the first part preferably is about 0.10weight percent or less, more preferably about 0.05 weight percent orless, even more preferably about 0.01 weight percent or less, and mostpreferably about 0.005 weight percent or less, based on the total weightof the first part, or based on the total weight of the matrix phase ofthe first part. The first part may even be total free of isocyanategroups. The molar ratio of isocyanate groups to carbamate groups in thefirst part preferably is about 0.35 or less, more preferably about 0.20or less, even more preferably about 0.10 or less, even more preferablyabout 0.03 or less, and most preferably about 0.01 or less. The molarratio of isocyanate groups to carbamate groups in the first part may beabout 0.00 or more.

The carbamate-containing compound preferably has an equivalent weight(i.e., molecular weight divided by number of carbamate groups) of about10,000 g/equivalent or less, more preferably about 7,000 or less, evenmore preferably about 4,000 or less, even more preferably about 3,000 orless, and most preferably about 2,000 or less. The carbamate-containingcompound may have an equivalent weight of about 300 g/equivalent ormore, about 500 g/eq or more, or about 700 g/eq or more. Thecarbamate-containing compound preferably has a number average molecularweight of about 20,000 g/mole or less, more preferably about 10,000 orless, even more preferably about 7,000 or less, even more preferablyabout 6,000 or less, and most preferably about 5,000 or less. Thecarbamate-containing compound preferably has a number average molecularweight of 500 g/mole or more, about 1000 g/mole or more, or about 1,500g/mole or more. Molecular Weight can be measured by gel permeationchromatography (GPC), for example with a Malvern Viscothek GPC maxequipment. Tetrahydrofuran (THF) is preferably used as an eluent, PL GELMIXED D (Ailent, 300*7.5 mm, 5 μm) may be used as a column, withrefractive index and/or light scattering detectors. For example, aMALVERN Viscotek TDA may be used as a detector.

The carbamate-containing compound may be prepared by reacting anisocyanate-containing compound including one or more isocyanate groupswith a phenol-containing compound including one or more phenol groups,wherein the resulting compound includes two or more carbamate groups.The isocyanate-containing compound may be a be a prepolymer. Anisocyanate containing prepolymer may be formed by reacting adiisocyanate compound with a polyol, where excess isocyanate is used sothat essentially all of the polyol is reacted. The diisocyanate mayinclude an aromatic isocyanate, an aliphatic isocyanate or both.Preferably, the diisocyanate includes or consists essentially of anaromatic diisocyanate. It will be appreciated that the diisocyanate maybe replaced by a compound including more than two isocyanate groups. Thepolyol preferably is a polyether polyol. The polyol may have two or moreOH groups. It will be appreciated that instead of using a prepolymer,the phenol-containing compound may be reacted directly with thediisocyanate. The phenol-containing compound typically has a linearhydrocarbon attached to the phenol group to provide some aliphaticcharacteristics to the compound. The linear hydrocarbon preferablyincludes about 3 or more carbon atoms, more preferably about 5 or morecarbon atoms, even more preferably about 8 or more carbon atoms, andmost preferably about 10 or more carbon atoms. The linear hydrocarbonpreferably includes about 50 or less carbon atoms, about 30 or lesscarbon atoms, about 24 or less carbon atoms, or about 18 or less carbonatoms. The phenol-containing compound preferably is a lipid.

An example of a carbamate containing-compound is a reaction product ofan aromatic polyisocyanate prepolymer (based on toluene diiosoyanatereacted with a polyether polyol, having an NCO content of about 4-5% andan equivalent weight of about 500-1500 g/eq) and phenol-containing lipid(such as cardanol). The compounds are preferably reacted in the presenceof a catalyst, heat, and an inert atmosphere. The reaction temperaturepreferably is about 30° C. or more, more preferably about 40° C. ormore. The reaction temperature is preferably about 130° C. or less, morepreferably about 100° C. or less. The catalyst may be a Lewis acid or aLewis base catalyst. A particularly preferred catalyst is a tincatalyst, particularly preferred is dioctyltin dineodecanoate, or anamine catalyst, particularly a tertiary amine catalyst, for exampleDABCO (1,4-diazabicyclo[2.2.2]octane).

The carbamate-containing compound may be a blocked isocyanate compound,where the isocyanate groups are blocked by phenol groups to formcarbamate groups. Although, such blocked isocyanate groups (i.e.,isocyanate groups that have been converted into a carbamate group) maybe unblocked by heating, it may be desirable to avoid heating thetwo-part composition after the parts are mixed and contacted with adevice (e.g., a heat generating device). As such, it may be desirable toreact the carbamate group with a compound of the second part, withoutunblocking the compound (i.e., without forming isocyanate groups).Therefore, the second part preferably includes one or morecarbamate-reactive compounds capable of reacting with the carbamategroups for polymerizing or cross-linking at least thecarbamate-containing compound. The carbamate-reactive compound may reactwith the carbamate groups to increase the viscosity of the composition.

The carbamate-reactive compound may include any carbamate-reactivegroups capable reacting with the carbamate group. Preferably thecarbamate-reactive compound includes one or more amine groups. The aminegroups may be any amine group (primary, secondary, or tertiary),preferred amine groups are primary and secondary amines, and mostpreferred amine groups are primary amines. The carbamate-reactivecompound preferably is a polyamine including two or more amine groups.For example, the carbamate-reactive compound may include a firstpolyamine having two amine groups and a second polyamine having morethan two amine groups. The amine groups of the polyamine are typicallyspaced apart by two or more backbone atoms (i.e., atoms defining theshortest covalent connection between the two groups). Preferably eachamine group is spaced apart from the other amine group(s) by 5 or morebackbone atoms, more preferably about 6 or more backbone atoms, evenmore preferably about 8 or more backbone atoms, and most preferablyabout 10 or more backbone atoms.

The carbamate-reactive component (e.g., the second part) may include oneor more polyols. However, any reaction between the polyol and the firstcomponent may be minimal, particularly for applications where theheating of the composition (e.g., after mixing) to a temperature ofabout 60° C. or more (or about 100° C. or more) is avoided. If polyol ispresent in the second part, the molar ratio, of the hydroxyl groups(e.g., of the polyol) to the amine groups (e.g., of the polyamine)preferably is about 1.5 or less, more preferably about 0.9 or less, evenmore preferably about 0.6 or less, and most preferably about 0.3 orless. The molar ratio o hydroxyl groups to amine groups in the secondpart may be about 0.0 or more, or about 0.01 or more.

Surface Modifier (for the Filler)

Although in many filled polymer systems, it is desirable to have goodcompatibility and/or bonding between the matrix phase and the fillerphase, it has surprisingly been determined that for these highly filledcompositions, such compatibility and/or bonding may create bridgesbetween neighboring filler particles that prevent the flow of thecomposition. It is preferred that the matrix phase material does notbond with a surface of the filler. For example, the covalent bonding,ionic bonding, and hydrogen bonding may be reduced, minimized or evencompletely avoided. This can be achieved by selection of the matrixphase material and conductive filler material. Alternatively, the fillermaterial may be treated with one or more surface modifiers for reducing,minimizing or eliminating bonding with the matrix phase material.

The surface modifier may partially or completely cover the surface ofthe conductive filler particle. The surface modifier may have one ormore functional groups that reacts with the conductive filler particle.As such, the surface modifier may be covalently bonded to the conductivefiller. By way of example, the conductive filler may include M-OHgroups, where Mis a metal atom, and the surface modifier may include afunctional group that reacts with the M-OH group to form a direct orindirect bond between the surface modifier and M.

The surface of the conductive filler may be hydrophobized with thesurface modifier. For example, the surface modifier may include an alkylcomponent and one or more functional group at or near one end of thealkyl component. The alkyl component preferably includes about 6 or morecarbon atoms, more preferably about 8 or more carbon atoms, even morepreferably about 10 or more carbon atoms, and most preferably about 12or more carbon atoms. The one or more functional groups may be selectedto react with surface of the conductive filler. For example, the one ormore function groups may include one or more alkoxysilanes. Such afunctional group may be particularly useful for bonding the surfacemodify to a conductive filler including M-OH groups, such as in aluminumhydroxide. An example of a reaction between a conductive filler and asurface modifier is shown in FIG. 3.

It will be appreciated that the surface modifier may be added to thefiller before or after mixing the conductive filler with the matrixphase material. For example, the conductive filler may be coated and/orreacted with the surface modifier prior to mixing the conductive fillerand the matrix phase material. As another example, the surface modifiermay be mixed with the matrix phase material to form a premix which isthen combined with the conductive filler. As another example, theconductive filler and the matrix phase material may be mixed and thenthe surface modifier may be added to the mixture.

As illustrated in FIG. 4(A), when a conductive filler having a narrowparticle size distribution is employed, the resulting composition mayhave a rough surface even when the filler loading is low, (e.g., onlyabout 60 weight percent). As illustrated in FIG. 4(B), the ability toincrease the filler loading is improved by using a filler having a broadparticle size distribution. As illustrated in FIG. 4(C), the ability toincrease the filler loading is further improved by using a filler havinga broad particle size distribution and also adding a surface modifierthat reduces, minimizes or eliminates bonding between the matrix phasematerial and the filler particles.

Catalyst

The composition preferably includes one or more catalysts foraccelerating a reaction between a carbamate-containing compound and acarbamate-reactive compound (such as a polyamine containing compound).The catalyst may include a Lewis acid or a Lewis base catalyst. TheLewis acid catalyst may be an organometallic compound, preferablyincluding one or more aliphatic groups. Each aliphatic group preferablyincludes four or more, six or more, or eight or more carbon atoms. Theorganometallic compound preferably is a tin compound. An example of atin-containing Lewis acid catalyst is dioctyltin dineodecanoate. The oneor more catalysts may include an amine catalyst. The amine catalystpreferably includes may include an aliphatic group, an aromatic group,or both. Examples of amine catalysts are tris-2,4,6-dimethylaminomethylphenol or DABCO (1,4-diazabicyclo[2.2.2]octane). The catalyst should beemployed in an amount sufficient for accelerating the reaction betweenthe carbamate containing compound and the polyamine. Preferably theamount of the catalyst is about 0.05 weight percent or more, morepreferably about 0.10 weight percent or more, even more preferably about0.20 weight percent or more, even more preferably about 0.4 weightpercent or more, and most preferably about 0.75 weight percent or more,based on the total weight of the matrix phase in the total composition(or based on the total weight of liquid materials int eh composition).Preferably, the amount of the catalyst is about 10 weight percent orless, more preferably about 8 weight percent or less, even morepreferably about 5 weight percent or less, and most preferably about 4weight percent or less, based on the total weight of the matrix phase inthe total composition (or based on the total weight of liquid materialsin the composition).

The catalyst may be provided in the first part, the second part, orboth. As one example, the first part and the second part may eachcontain both an amine catalyst and an organometallic catalyst (e.g., atin-containing Lewis acid catalyst). As another example, one part (e.g.,the first part or the second part) may include an organometalliccatalyst (e.g., a tin-containing Lewis acid catalyst) and the other partmay include an amine catalyst. As another example the first part and thesecond part may both include an organometallic catalyst (e.g., atin-containing Lewis acid catalyst) which may be the same or different.

Preferred catalysts are liquid at room temperature.

Plasticizer

The first part, the second part, or both parts may include one or moreplasticizers. The plasticizer preferably is a compound that does notreact with the carbamate group of the first part. The plasticizerpreferably is a compound that does not react with an amine group of thesecond part. The plasticizer is a liquid at room temperature and forms aportion of the matrix phase. The plasticizer may be present in the firstpart, the second part, or both, an amount of about 0 weight percent ormore, preferably about 10 weight percent or more, more preferably about20 weight percent or more, and most preferably about 25 weight percentor more, based on the total weight of the matrix phase of the part. Theplasticizer may be present in the first part, the second part, or both,an amount of about 75 weight percent or less, preferably about 65 weightpercent or less, more preferably about 60 weight percent or less, andmost preferably about 55 weight percent or less, based on the totalweight of the matrix phase of the part.

Preferred plasticizers have a weight average molecular weight of about2,000 g/mole or less, more preferably about 1,000 g/mole or less, evenmore preferably about 800 g/mole or less, and most preferably about 600g/mole or less. The plasticizer is a liquid at a temperature of about100° C. Preferred plasticizers have a molecular weight of about 125g/mole, more preferably about 175 g/mole, and most preferably about 225g/mole.

Colorant

The composition may optionally include a dye, pigment, or other colorantfor providing a predetermined color to the composition. The colorant, ifemployed may be included in the first part, the second part, or both.The colorant typically is present in an amount of about 1 weight percentor less, about 0.5 weight percent or less, or about 0.2 weight percentor less, based on the total weight of the two-part composition. Thecolorant may be provided as a neat material or may be mixed with acarrier material (typically a carrier liquid). The carrier materialpreferably is a material described herein for use in the first partand/or the second part. For example, the carrier material may be anepoxy resin, a carbamate-containing compound, a plasticizer, polyol, acatalyst, a carbamate-reactive compound, or a surface modifier;according to the teachings herein.

The matrix phase (e.g., as defined by the liquid compounds, and/or thecomposition including the filler) of the first part preferably includesa substantial amount of the carbamate-containing compound. Preferablythe amount of the carbamate-containing compound in the first part isabout 10 weight percent or more, more preferably about 15 weight percentor more, and most preferably about 18 weight percent or more, based onthe total weight of the liquid compounds in the first part. The amountof the carbamate-containing compound in the first part may be about 90weight percent or less, about 80 weight percent or less, about 70 weightpercent or less, about 60 weight percent or less, or about 50 weightpercent or less, based on the total weight of the liquid compounds inthe first part.

The matrix phase (e.g., as defined by the liquid compounds, and/or thecomposition including the filler) of the second part preferably includesa substantial amount of the carbamate-reactive compound (e.g., thepolyamine). Preferably the amount of the carbamate-reactive compound inthe second part is about 10 weight percent or more, more preferablyabout 15 weight percent or more, even more preferably about 20 weightpercent or more, and most preferably about 25 weight percent or more,based on the total weight of the liquid compounds in the second part.The amount of the carbamate-reactive compound (e.g., polyamine) in thesecond part may be about 90 weight percent or less, about 80 weightpercent or less, about 70 weight percent or less, about 60 weightpercent or less, or about 50 weight percent or less, based on the totalweight of the liquid compounds in the second part.

The total amount of the carbamate-containing compound, the one or morecatalysts, the carbamate-reactive compound, the surface modifier, theone or more fillers, and the plasticizer preferably is about 95 weightpercent or more, more preferably about 97 weight percent or more, evenmore preferably about 98 weight percent or more, even more preferablyabout 99 weight percent or more, and most preferably about 99.5 weightpercent or more, based on the total weight of the composition. The totalamount of the carbamate-containing compound, the one or more catalysts,the polyamine compounds, the alkoxysilane surface modifier, the ATH, theoptional calcium carbonate and calcium oxide, and the plasticizerpreferably is about 95 weight percent or more, more preferably about 97weight percent or more, even more preferably about 98 weight percent ormore, even more preferably about 99 weight percent or more, and mostpreferably about 99.5 weight percent or more, based on the total weightof the composition.

A molar ratio of the carbamate groups in the first part to the aminegroups in the second part preferably is about 0.1 or more, about 0.2 ormore, about 0.3 or more, about 0.4 or more, about 0.5 or more, or about0.6 or more. A molar ratio of the carbamate groups in the first part tothe amine groups in the second part preferably is about 10 or less,about 5.0 or less, about 3.5 or less, about 2.5 or less, about 2.0 orless, or about 1.7 or less.

Gap Filling Properties

The two-part composition should be able to fill a gap between componentsand provide for a thermally conductive path between the two components.Typically, the two-part composition, after mixing (i.e., the thermalinterface material), is placed on one of the components and then theother component is pressed into the mixture. Each of the two-parts ofthe thermal interface material preferably has a sufficiently lowviscosity so that the material can be mixed with the other part and acomponent can easily be pressed into the mixture. The two-partcomposition, after mixing, should have a sufficiently high viscosity sothat the mixture does not flow away from the region in which it isapplied (e.g., before pressing the second component into the mixture).The viscosity of one of the parts or of the mixture may be characterizedby a PRESS-IN FORCE, as herein. Preferably the first part, the secondpart, the mixture, or any combination thereof is characterized by apress-in force (initial, measured at 23° C.) of about 1000 N or less,about 900 N or less, about 800 N or less, about 700 N or less, about 600N or less, about 500 N or less, or about 400 N or less. Preferably thefirst part, the second part, the mixture, or any combination thereof ischaracterized by a press-in force (initial, measured at 23° C.) of about5 N or more, about 10 N or more, about 30 N or more, about 60 N or more,about 80 N or more, about 90 N or more, or about 100 N or more.

Shelf Stability

The materials according to the teachings herein may be required to beshelf stable at room temperature and/or at shipping temperatures. Theshelf stability of the material may be characterized by acceleratedtesting whereby the material is exposed to a temperature of about 55° C.for 3 days. Preferably, each part of the two-part composition maintainsits good viscosity even after aging at about 3 days at a temperature ofabout 55° C., prior to mixing. In particular, the first part, the secondpart, or both should be selected so that there is little or no increasein viscosity after aging for 3 days at 55° C. Preferably each part ischaracterized by a ratio of the press-in force after aging (e.g., 3 daysat 55° C.) to an initial press-in force of about 4.0 or less, about 3.0or less, about 2.0 or less, about 1.5 or less, or about 1.3 or less.Typically, the ratio of the press-in force after aging to the initialpress-in force is about 0.5 or more, 0.75 or more, or about 1.0 or more;however, values of 0.5 or less are also possible. After aging (e.g., 3days at 55° C.), the press-in force of the first part, the second part,or both, preferably is about 1000 N or less, about 900 N or less, about800 N or less, about 700 N or less, about 600 N or less, about 500 N orless, or about 400 N or less.

Applications

The thermal interface material according to the teachings herein may beused in any device or system requiring polymeric or oligomeric materialhaving good thermal conductivity. FIG. 5 is a drawing of illustratingfeatures of a device 10 including a thermal interface material 12. Thedevice may require heat flow 20 from a first component 14 of the device,to a second component 16 of the device 10. As illustrated in FIG. 5, theheat flow may go through the thermal interface material 12. The secondcomponent 16 of the device may have a surface 20 (internal or external)that allows for removal of heat from second component.

The thermal interface material may be used as a gap fill material. Thethermal interface material may be used as a sealing material. In someapplications, it may be necessary to apply thin layers of the thermalinterface material (e.g., about 2 mm or less, about 1 mm or less, about0.5 mm or less or about 0.3 mm or less). As such, the thermal interfacematerial preferably has a low viscosity and/or has a good mixingbehavior (e.g., having a smooth appearance that does not crumble aftermixing) so that thin regions or layers may be prepared.

Article including one or more battery cells, a cell cover having asurface for contacting with a cooling unit or with a circulating coolingfluid, preferably have a thermal interface material interposed betweenthe battery cell and the cell cover. The thermal interface materialprovides a path for conducting thermal energy from the battery cell tothe cell cover for managing the temperature of the battery cell. Thebattery cells may be provided as one or more modules. Without thethermal interface material, there may be a gap (at least in someregions) between the battery module and a conductive plate (e.g., of ahousing). FIG. 6 is a drawing illustrating features that may be employedin thermal management of one or more battery modules. Thebattery/thermal management system 30 includes a thermal interfacematerial 32 for filling a gap between one or more battery modules 34 anda metal surface 36. The thermal interface material may be applied byplacing on a surface of the battery modules or by placing on the metalsurface. The metal surface may be a cooling plate or other componentarranged for drawing heat out of the system.

Test Methods

Particle size distribution.

Unless otherwise stated, the particle size distribution of the filler ismeasured by laser diffraction in acetone.

Thermal Conductivity

Thermal conductivity is measured according to ASTM 5470-12 on a thermainterface material tester from ZFW Stuttgart. The tests are performed inSpaltplus mode at a thickness of between 1.8-1.2 mm. The describedthermal interface material is considered as Type I (viscous liquids) asdescribed in ASTM 5470-12. The upper contact is heated to ca 40° C. andthe lower contact to ca 10° C., resulting in a sample temperature of ca25° C. The A and B component are mixed with a static mixer when appliedfrom a manual cartridge system. This is the method that is used in theExamples of the present application.

Press-in Force

The press-in force is measured with a tensiometer (Zwick). Thecomposition (e.g., the gap filler material) is placed on a metalsurface. An aluminum piston with a diameter of about 40 mm diameter isplaced on top and the material is compressed to an initial position of 5mm. The material is then compressed from 5 mm to 0.3 mm at a velocity ofabout 1 mm/s velocity and force deflection curve is recorded. The force(N) at 0.5 mm thickness is then reported in the datatable and consideredas the press-in force. A material having a low viscosity has a press-inforce of 700 N or less. A high viscosity material has a press-in forcegreater than 700 N, or about 800 N or more. A material having a lowviscosity preferably has a press-in force of about 600 N or less, evenmore preferably about 500 N or less, and most preferably about 400 N orless.

Mixing Ability

The ability to mix the composition was determined by the ability tocreate a single mass of material having a smooth surface. Such materialshaving “good” mixing. When the surface is rough and/or the materialcrumbles upon removing from the mixer, the mixing is poor.

Materials

Polyisocyanate An aromatic polyisocyanate prepolymer based on toluenePrepolymer -1 diisocyanate (TDI). NCO content is about 4.2 to 4.6% (ISO11909). Viscosity is about 6,000 to 8,000 (ISO 3219/A3). Equivalentweight is about 950. Reaction product of TDI and a polyether polyol.Polyisocyanate An aliphatic polyisocyanate prepolymer based onPrepolymer -2 hexamethylene diisocyanate (HDI). NCO content is about6.6% (ISO 11909). Reaction product of HDI and a polyether polyol.Cardanol Cardanol is a phenolic lipid obtained from cashew nut having aterminal phenol group attached to a linear C₁₅ hydrocarbon (typicallyincluding a combination of two or more of: tri-unsaturated,bi-unsaturated, mono- unsaturated, and saturated C₁₅ groups).Approximately: Ph-C₁₅H₂₇. Carbamate Reaction product of 22.1 wt. %cardanol; 77.85 wt. % Prepolymer-1 Polyisocyane Prepolymer-1; and 0.05wt. % dibutyl tin dilaurate Filler-1 Filler-1 is an aluminum hydroxidehaving a broad particle size distribution including D₁₀, D₅₀, and D₉₀ ofabout 0.5 μm, about 8 μm, and about 80 μm, respectively; a sieve residue(>45 μm) of about 35%, and Al(OH)₃ concentration of about 99.7 wt. %.D₉₀/D₅₀ is about 10 and D₉₀/D₁₀ is about 160. It is believed that ATH-1has a bimodal particle size distribution with an average size of thesmaller particles being less than about 10 μm and the average size ofthe larger particles being greater than about 50 μm. Particle size ismeasured according to ISO 13320, using a 2.24 × 10⁻³M solution ofTetrasodium pyrophosphate decahydrate (1 g Na₄P₂O₇ × 10H₂O in 1000 mldeionized water) as dispersion medium. Filler-2 Filler-2 is a CALOFORTSV calcium carbonate commercially available from CARY COMPANY. FattyAcid-1 Fatty Acid-1 is a methyl ester of an unsaturated C₁₆-C₁₈ fattyacid EPDXY A liquid epoxy resin that is a reaction product of RESIN - 1epichlorohydrin and propylene glycol having an epoxide equivalent weightof about 320 g/eq (ASTM D-1652); a concentration of epoxide groups ofabout 13.0-13.9% (ASTM D-1652); a viscosity at 25° C. of about 65 (ASTMD-445); a density of about 1.06 g/ml (ASTM D-4052); and a flash point ofabout 194° C. (ASTM D-3278). POLYAMINE-1 Polyamine-1 is a difunctionalamine having an average of (polyoxy- about two spaced apart —NH₂ groups.This polyamine has propylene a number average molecular weight of about2000 g/mole. diamine) The concentration of amine is about 0.96-1.05meq/g. About 97% of the amines are primary amines. The amine hydrogenequivalent weight is about 514 g/eq, and the Brookfieldviscosity isabout 247 cpt at 25° C. POLYAMINE-2 Polyamine-2 is a trifunctional aminehaving an average of (Glyceryl about three spaced apart —NH₂ groups.This polyamine is poly(oxy- a polyetheramine having a number averagemolecular proylene) weight of about 3000 g/mole. The concentration ofamine triamine) is about 0.90-0.98 meq/g. About 97% of the amines areprimary amines. The amine hydrogen equivalent weight is about 530 g/eq,and the viscosity is about 367 cSt at 25° C. POLYAMINE-3 Polyamine-3 isa difunctional amine having an average of (polyoxy- about two spacedapart —NH₂ groups. This polyamine has propylene a number averagemolecular weight of about 430 g/mole. diamine) The concentration ofamine is about 4.1-4.7 meq/g. About 97% of the amines are primaryamines. The amine hydrogen equivalent weight is about 115 g/eq, and theviscosity is about 22 cSt at 25° C. POLYOL-1 Polyether diol based onpropylene glycol having a number average molecular weight of about 1000g/mole; a hydroxyl number (as KOH) of about106-114 mg/g (ASTM D 4274D);a viscosity of about 135-155 cSt (ASTM D 4878). POLYOL-2 Polyether triolhaving a hydroxyl number of about 56 and a viscosity of about 485 mPa-sat 25° C. POLYOL-3 Polyol-3 is linear polyester diol derived fromcaprolactone monomer, terminated by primary hydroxyl groups. It is awhite waxy solid with a melting point between 40-50° C. and an hydroxylvalue of 54-58 mg KOH/g. COLORANT-1 Green dye dispersed in a liquidepoxy resin Dibutyltin Lewis Acid Catalyst dilaurate AMINETris-2,4,6-dimethylaminomethyl phenol is an amine CAT-1 catalyst havingan amine valude of about 630 mg KOH/g; a viscosity of about 120-250mPa-s at 25° C.; and a boiling point of about 250° C. DABCO (1,4- Lewisbase catalyst diazabicy- DABCO LV33 (from Evonik: 33% 1,4-clo[2.2.2]octane) diazabicyclo[2.2.2]octane in dipropyleneglycol)

EXAMPLES

Carbamate Prepolymer-1

The Carbamate Prepolymer-1 is prepared using the composition shown inTABLE 2.

The cardanol and polyisocyanate prepolymer-1 are added to a reactor andheated to about 60° C. with continuous mixing. Dibutyltin dilauratecatalyst is then added and the reaction is carried out under nitrogen ata temperature of about 80° C. for about 45 minutes. After 45 minutes, avacuum applied for 10 minutes and the reactor is cooled to roomtemperatures. The reaction product (Carbamate Prepolymer-1) has thefollowing properties shown in TABLE 2. Molecular Weight data of thepolyurethane prepolymers were measured by gel permeation chromatography(GPC) with a Malvern Viscothek GPC max equipment. EMSURE—THF (ACS, Reag.Ph EUR for analysis) was used as an eluent, PL GEL MIXED D (Ailent,300*7.5 mm, 5 μm) was used as a column, and MALVERN Viscotek TDA wasused as a detector.

TABLE 2 Composition and properties of Carbamate Prepolymer-1 CarbamatePrepolymer-1 Polyisocyanate Prepolymer-1 Weight % Cardanol Weight %Dibutyltin dilaurate catalyst Weight % Total 100 Viscosity at 23° C. Pa· s 45 NCO Content (upper limit) Weight % ≤0.8 NCO Content (lower limit)Weight % ≥0.0 Weight Averager Molecular g/mole (GPC) 3500 WeightPolydispersity Index (GPC) 1.1′

Examples A-1, A-2, A-3, and A-4 are part A composition including anisocyanate prepolymer. These compositions are prepared by first mixingthe liquid components and then adding the filler in the amounts shown inTABLE 3. A planetary mixer is used for mixing all of the part Acompositions and for mixing all of the part B compositions thematerials. Examples A-1, A-2, A-3, and A-4 all have high initialPress-In forces and also become solid after 3 days at 55° C., as shownin Table 3.

Thermal conductivity was measured according to ASTM 5470-12 on a thermainterface material tester from ZFW Stuttgart, with tests performed inSpaltplus mode at a thickness of between 1.8-1.2 mm; the describedthermal interface material is considered as Type I (viscous liquids) asdescribed in ASTM 5470-12, the upper contact is heated to ca 40° C. andthe lower contact to ca 10° C., resulting in a sample temperature of ca25° C.

TABLE 3 COMPONENT-A COMPOSITIONS (HAVING AN ISOCYANATE PREPOLYMER)EXAMPLE EXAMPLE EXAMPLE EXAMPLE A-1 A-2 A-3 A-4 Polyisocyanate 5.0 10.0Prepolymer-1 (wt. %) Polyisocyanate 5.0 4.0 Prepolymer-2 (wt. %)Filler-1 (wt. %) 90.0 85.0 90.0 88.0 Fatty Acid-1 (wt. %) 4.0 4.0 4.06.0 Hexadecyltrimethoxysilane (wt. %) 1.0 1.0 1.0 2.0 Total 100.0 100.0100.0 100.0 Ability to mix Good Good Good Good Initial Press-In Force,(N) 1056 538 975 427 Press-In Force after 3 Solid Solid Solid Solid days@ 55° C., (N) Thermal conductivity, λ (W/mK) — — — 2.35

In Examples A-4, A-5, A-6, A-7, and A-8, the addition of extra silanecompound and/or the additional of dimethyl malonate appear to reduce theinitial press-in force. However, all of these materials have poor shelfstability as shown by the solidifying of the composition after 3 days at55° C., such that the composition can no longer be tested for press-inforce, as shown in Table 4.

TABLE 4 COMPONENT-A COMPOSITIONS (HAVING AN ISOCYANTE PREPOLYMER)EXAMPLE EXAMPLE EXAMPLE EXAMPLE A-5 A-6 A-7 A-8 PolyisocyanatePrepolymer-1 (wt. %) — — — — Polyisocyanate Prepolymer-2 (wt. %) 7.0 7.34.0 4.0 Filler-1 (wt. %) 87.0 86.0 88.0 88.0 Fatty Acid-1 (wt. %) 3.04.7 5.5 5.0 Hexadecyltrimethoxysilane (wt. %) 3.0 2.0 2.0 2.0Dimethylmalonate — — 0.5 1.0 Total 100.0 100.0 100.0 100.0 Ability tomix Good Good Good Good Initial Press-In Force, (N) 368 311 206 152Press-In Force after 3 Solid Solid Solid Solid days @ 55° C., (N)Thermal conductivity, λ (W/mK) — 2.17 — —

Example B-1 is a part B composition including a polyol component andhaving the composition shown in Table 5.

TABLE 5 COMPONENT-B COMPOSITION (HAVING A POLYOL) EXAMPLE B-1 POLYOL-1(wt. %) 5.0 Filler-1 (wt. %) 90 Fatty Acid-1 (wt. %) 3.85Hexadecyltrimethoxysilane (wt. %) 1.0 Dioctyltin thioglycolate catalyst0.15 Total 100.0 Ability to mix Good Initial Press-In Force, (N) 139Thermal conductivity, λ (W/mK) 3.02

Examples A-9, A-10, A-11, A-12, A-13, A-14, A-15, A-16, A-17, A-18,A-19, and A-20 are Part A compositions are prepared usingCarbamate-Prepolymer-1, the compositions and properties of thesecompositions are shown in Tables 7, 8 and 9. Here, it is seen that it ispossible to prepare a part A composition with low initial viscosity,good thermal stability, and high thermal conductivity.

TABLE 6 COMPONENT-A COMPOSITIONS (HAVING A CARBAMATE PREPOLYMER) EXAMPLEEXAMPLE EXAMPLE EXAMPLE EXAMPLE A-9 A-10 A-11 A-12 A-13 CarbamatePrepolymer-1 2.0 4.0 4.0 3.0 3.0 (wt. %) Epoxy Resin-1 (wt. %) 2.0 — — —1.0 Filler-1 (wt. %) 88.0 88.0 90.0 90.5 91.0 Filler-2 (wt. %) 2.0 — — —— Fatty Acid-1 (wt. %) 5.75 6.0 4.0 4.5 3.0 Hexadecyltrimethoxysilane —2.0 2.0 2.0 2.0 (wt. %) Dioctyltin dineodecanoate 0.15 — — — — (wt. %)Colorant-1 (wt. %) 0.1 — — — — Total 100.0 100.0 100.0 100.0 100.0Ability to mix Good Good Good Good Good Initial Press-In Force, (N) 22658 150 175 269 Press-In Force after 3 days 224 102 250 — — @ 55° C., (N)Thermal conductivity, λ — — 3.06 3.22 — (W/mK)

TABLE 7 COMPONENT-A COMPOSITIONS (HAVING A CARBAMATE PREPOLYMER) EXAMPLEEXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE A-14 A-15 A-16A-17 A-18 A-19 A-20 A-21 Carbamate 3.0 3.0 3.0 2.0 2.5 2.0 2.0 2Prepolymer-1 (wt. %) Epoxy Resin-1 (wt. %) — — — 1.5 1.5 3.0 3.0 0.5Filler-1 (wt. %) 90.4 89.4 88.4 88.0 88.0 89.0 89.0 87.6 Filler-2 (wt.%) — 1.0 2.0 2.0 2.0 1.0 1.0 2 Fatty Acid-1 (wt. %) 4.5 4.5 4.5 6.255.75 3.9 3.75 3.35 Tris(2-ethylhexyl) — — — — — — — 3.3 phosphatePOLYOL-3 — — — — — — — 0.15 Hexadecyltri- 2.0 2.0 2.0 — — 1.0 1.0 1.0methoxysilane (wt. %) Dioctyltin — — — 0.15 0.15 — 0.15 — dineodecanoate(wt. %) Colorant-1 (wt. %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Total 100.0100.0 100.0 100.0 100.0 100.0 100.0 100.0 Ability to mix Good Good GoodGood Good Good Good Good Initial Press-In Force, (N) 201 199 232 285 284— — 210 Press-In Force after 3 472 261 331 — — — — — days @55° C., (N)Thermal conductivity, λ 3.11 3.19 3.19 — — — — 3.11 (W/mK)

Examples B-2, B-3, B-4, B-5, B-6, B-7, and B-8 are part B compositionsincluding a carbamate-reactive compound (e.g., a polyamine) capable ofreacting with a part A composition including a carbamate-containingcompound.

TABLE 9 COMPONENT-B COMPOSITIONS (HAVING A POLYAMINE) EXAMPLE EXAMPLEEXAMPLE EXAMPLE EXAMPLE EXAMPLE B-2 B-3 B-4 B-5 B-6 B-9 Polyamine-1, 1.52.5 3.0 2.5 3.0 — difunctional (wt. %) Polyamine-2, 1.5 — — — — 1.67trifunctional (wt. %) Filler-1 (wt. %) 88.0 90.5 90.5 89.5 88.0 88.9Filler-2 (wt. %) 2.0 — — 1.0 2.0 2.0 Fatty Acid-1 (wt. %) 4.5 5.3 4.75.3 4.5 3.1 Tris(2-ethylhexyl) — — — — — 3.08 phosphate (wt. %) POLYOL-3— — — — — 0.15 Hexadecyltri- 2.0 1.5 1.5 1.5 2.0 1.0 methoxysilane (wt.%) DABCO LV33 — — — — — 0.1 Tris-2,4,6-dimethyl- 0.5 — — — 0.5 —aminomethyl phenol (wt. %) Dioctyltin — 0.15 0.15 0.15 — —dineodecanoate (wt. %) 2,2′-Dimorpholinyl- — 0.05 0.15 0.05 — —diethylether (wt. %) Total 100.0 100.0 100.0 100.0 100.0 100.0 Abilityto mix Good Good Good Good Good Good Initial Press-In Force, (N) 102 366492 373 123 209 Press-In Force after 3 108 — — — — — days @55° C., (N)Thermal conductivity, λ — 3.11 — 3.06 — — (W/mK)

TABLE 10 COMPONENT-B COMPOSITIONS (HAVING A POLYAMINE) EXAMPLE EXAMPLEB-7 B-8 Polyamine-1, difunctional (wt. %) 2.5 2.5 Polyamine-3,difunctional (wt. %) 0.5 0.5 Filler-1 (wt. %) 89.0 89.0 Filler-2 (wt. %)1.0 1.0 Fatty Acid-1 (wt. %) 5.0 4.8 Hexadecyltrimethoxysilane (wt. %)1.0 1.0 Tris-2,4,6-dimethylamino- — 0.20 methyl phenol (wt. %) POLYOL-2(wt. %) 1.0 1.0 Total 100.0 100.0 Ability to mix Good Good

Examples 1 and 2 are 2-part compositions based on a first part includingan isocyanate and a second part including a polyol capable of reactingwith the isocyanate. These compositions are shown in Table 11.

TABLE 11 TWO-COMPONENT COMPOSITIONS (BASED ON ISOCYANATE A COMPONENT ANDPOLYOL B COMPONENT) EXAM- EXAM- PLE 1 PLE 2 A-Component (50 Exam- Exam-volume %) ple A-4 ple A-6 B-Component (50 Exam- Exam- volume %) ple B-1ple B-1 Average ATH 89 88 concentration (wt. %) Average calciumcarbonate 0 0 concentration (wt. %) Average total filler 89 88concentration (wt. %) Thermal conductivity, 2.76 2.63 λ (W/mK) InitialPress-In Force, (N) 291 364 Press-In Force after 24 — 876 hours at 23C., (N) Press-In Force after 72 — 1397 hours at 23 C., (N) Press-InForce after 168 1147 1739 hours at 23 C., (N)

Examples 3-14 are thermal interface materials based on acarbamate-containing A component and a polyamine containing B component.As shown in Tables 12 and 13, when the carbamate-containing A componentand the polyamine containing B component are mixed, the composition hasa generally low initial press-in force that allows filling of a gap.This is even possible when the thermal conductivity is about 3 W/mK. Forexample, when the composition includes more than 85 weight percentaluminum hydroxide and/or 89 weight percent or more total concentrationof filler.

TABLE 12 TWO-COMPONENT COMPOSITIONS (BASED ON CARBAMATE-CONTAINING ACOMPONENT AND POLYAMINE-CONTAINING B COMPONENT) EXAMPLE EXAMPLE EXAMPLEEXAMPLE 3 4 5 6 A-Component Example Example Example Example (50 volume%) A-9 A-12 A-13 A-14 B-Component Example Example Example Example (50volume %) B-2 B-3 B-4 B-3 Average ATH 88 90.5 90.75 90.45 concentration(wt. %) Average CaCO₃ concen- 2 0 0 0 tration (wt. %) Average totalfiller 90 90.5 90.75 90.45 concentration (wt. %) Thermal conductivity, λ3.03 2.98 2.90 2.93 (W/mK) Initial Press-In Force, (N) 181 232 — 270Press-In Force after 24 737 1719 — 975 hours at 23 C., (N) Press-InForce after 72 Cured 1719 — — hours at 23 C., (N) Press-In Force after168 — 2091 — 4939 hours at 23 C., (N)

TABLE 13 TWO-COMPONENT COMPOSITIONS (BASED ON CARBAMATE-CONTAINING ACOMPONENT AND POLYAMINE-CONTAINING B COMPONENT) EXAMPLE EXAMPLE EXAMPLEEXAMPLE 7 8 9 10 A-Component Example Example Example Example (50 volume%) A-15 A-9 A-17 A-18 B-Component Example Example Example Example (50volume %) B-5 B-6 B-2 B-2 Average ATH 89.45 88.0 88.0 88.0 concentration(wt. %) Average CaCO₃ 1.0 2.0 2.0 2.0 concentration (wt.%) Average totalfiller 90.45 90.0 90.0 90.0 concentration (wt. %) Thermal conductivity,— — — — λ (W/mK) Initial Press-In Force, (N) 227 151 145 176 Press-InForce after 4 538 — — — hours at 23 C., (N) Press-In Force after 24 —703 738 980 hours at 23 C., (N)

TABLE 14 shows the importance of having a catalyst in the A Componentand/or in the B-Component for affecting an increase in the viscosity (ascharacterized by the press-in force) at room temperature.

TABLE 14 TWO-COMPONENT COMPOSITIONS (BASED ON CARBAMATE- CONTAINING ACOMPONENT AND POLYAMINE-CONTAINING B COMPONENT) EXAMPLE EXAMPLE EXAMPLEEXAMPLE EXAMPLE 11 12 13 14 15 A-Component (50 volume %) Example ExampleExample Example Example A-19 A-19 A-20 A-20 A-21 B-Component (50 volume%) Example Example Example Example Example B-5 B-6 B-2 B-2 B-9 AverageATH concentration 89.0 89.0 89.0 89.0 88.05 (wt. %) Average CaCO₃ 1.01.0 1.0 1.0 2 concentration (wt. %) Average total filler 90.0 90.0 90.090.0 90.05 concentration (wt. %) Alkyl-Sn Catalyst in A- No No Yes YesNo Component Amine catalyst in B- No Yes No Yes — Component Lewis basecomponent in B- — — — — Yes Component (DABCO) Initial Press-In Force,(N) 147 160 256 228 133 Press-In Force after 1 hour at — — — — 186 23C., (N) Press-In Force after 2 hours — — — — 1965 at 23 C., (N) Press-InForce after 24 hours 214 222 396 395 cured at 23 C., (N) Press-In Forceafter 48 hours 232 237 520 378 — at 23 C., (N) Press-In Force after 72hours 229 424 450 481 — at 23 C., (N) Thermal conductivity, λ — — — —3.0 (W/mK)

What is claimed is:
 1. A two-part composition for a thermal interfacematerial comprising: i) a first part comprising at least a) a prepolymerincluding two or more carbamate groups; ii) a second part comprising atleast: b) one or more polyamine compounds capable of a reaction with theprepolymer; wherein the composition includes: c) one or more catalystsfor catalyzing the reaction between the prepolymer and the polyaminecompounds; and d) 50 weight percent or more of one or more conductivefillers, based on the total weight of the two-part composition.
 2. Thetwo-part composition of claim 1, wherein the prepolymer is formed byblocking one or more of the isocyanate groups (preferably substantiallyeach, or entirely each of the isocyanate groups) of an aromatic aromaticpoolyisocyanate prepolymer with a phenol group of a blocking compound.3. The two-part composition of claim 2, wherein the blocking compoundincludes a terminal phenol group (preferably a single terminal phenolgroup) attached to a linear hydrocarbon (preferably the linearhydrocarbon includes 6 or more, 8 or more, 10 or more, or 12 or morecarbon atoms) (preferably the linear carbon includes 60 or less, 30 orless, or 20 or less carbon atoms).
 4. The two-part composition of claim1, wherein the one or more polyamines, the prepolymer, or both have anaverage functionality of greater than
 2. 5. The two-part composition ofclaim 1, wherein the one or more thermally conductive fillers includes afiller selected from aluminum hydroxide, aluminium oxide, aluminiumpowder, zinc oxide, boron nitride, and/or mixtures of any of these. 6.The two-part composition of claim 1, wherein the one or more thermallyconductive fillers include a filler selected from aluminum hydroxide,aluminium oxide, and/or mixtures of any of these.
 7. The two-partcomposition of claim 1, wherein the one or more thermally conductivefillers is aluminum hydroxide.
 8. The two-part composition of claim 1,wherein the one or more conductive fillers includes aluminum hydroxide.9. The two-part composition of claim 1, wherein the first part includes75 weight percent or more aluminum hydroxide and the second partincludes 75 weight percent or more aluminum hydroxide.
 10. The two-partcomposition of claim 1, wherein a surface of the aluminum hydroxide ispartially or entirely coated with a surface modifier for reducing thehydrophilicity of the surface.
 11. The two-part composition of claim 1,wherein the composition includes an aluminum hydroxide having a broadparticle size distribution, including a D₉₀/D₅₀ ratio of about 3 ormore, wherein the particle size is measured according to ISO 13320,using a 2.24×10⁻³ M solution of Tetrasodium pyrophosphate decahydrate (1g Na₄P₂O₇X10H₂O in 1000 ml deionized water) as dispersion medium. 12.The two-part composition of claim 1, wherein the composition includesone or more plasticizers.
 13. The two-part composition of claim 1,wherein the composition includes a fatty acid or an ester of a fattyacid.
 14. The two-part composition of claim 1, wherein the compositioncomprises an epoxy resin in the first part, preferably wherein a weightratio of the prepolymer to the epoxy resin is about 0.5 or more, morepreferably about 0.8 or more, even more preferably about 1.0 or more.(Preferably the weight ratio of the prepolymer to the epoxy resin isabout 10 or less, about 5 or less, or about 4 or less).
 15. The two-partcomposition of claim 1, wherein the composition is substantially free ofisocyanate containing compounds (e.g., the amount of NCO in thefirst-part preferably is about 0.10 weight percent or less, about 0.05weight percent or less, or about 0.01 weight percent or less, based onthe total weight of the first part).
 16. The two-part composition ofclaim 1, wherein a molar ratio of the carbamate groups in the first partto the amine groups in the second part is about 0.1 or more, about 0.2or more, about 0.3 or more, about 0.4 or more, about 0.5 or more, orabout 0.6 or more and/or about 10 or less, about 5.0 or less, about 3.5or less, about 2.5 or less, about 2.0 or less, or about 1.7 or less. 17.The two-part composition of claim 1, wherein the first part includescalcium carbonate (preferably in an amount of about 0.1 weigh percent ormore, more preferably about 0.5 weight percent or more, and mostpreferably about 1.0 weight percent or more, based on the total weightof the first part).
 18. The two-part composition of claim 1, wherein thecatalyst is a Lewis acid or a Lewis base.
 19. The two-part compositionof claim 1, wherein the catalyst is a tin catalyst.
 20. The two-partcomposition of claim 1, wherein the catalyst is an amine catalyst. 21.The two-part composition of claim 1, wherein the catalyst is DABCO(1,4-diazabicyclo[2.2.2]octane).
 22. The two-part composition of claim1, wherein the first part includes some or all of the catalyst.
 23. Thetwo-part composition of claim 1, wherein the composition ischaracterized by a thermal conductivity of about 2.0 W/mK or more(preferably about 2.5 or more, more preferably about 2.8 or more, evenmore preferably about 2.9 or more, and most preferably about 3.0 ormore), measured according to ASTM 5470-12 on a therma interface materialtester from ZFW Stuttgart, with tests performed in Spaltplus mode at athickness of between 1.8-1.2 mm; the described thermal interfacematerial is considered as Type I (viscous liquids) as described in ASTM5470-12, the upper contact is heated to ca 40° C. and the lower contactto ca 10° C., resulting in a sample temperature of ca 25° C.
 24. Thetwo-part composition of claim 1, wherein the two-part composition curesat room temperature (preferably as characterized by an increase in apress-in force of about 100% or more, after aging for 24 hours aftermixing).
 25. The two-part composition of claim 1, wherein the first partis shelf stable (e.g., as characterized by a press-in force of the firstpart of less than 700 N after aging for 3 days at 55° C.).
 26. Anarticle comprising: a first component that generates heat, a secondcomponent for removing heat, and a layer of a thermal interface materialinterposed between the first and second components, wherein the thermalinterface material provides a path for transferring a heat from thefirst component to the second component and is formed of the two-partcomposition of claim
 1. 27. A method comprising a step of: arranging alayer of a thermal interface material between a first component and asecond component, and applying a pressure so that the thermal interfacematerial contacts both the first component and the second component andfills a gap between the two components, wherein the thermal interfacematerial is formed of a two-part composition of claim 1.